In the depths of the oceans dwell myriads of fascinating life forms, relics of the forgotten past and countless mysteries that continue to baffle mankind. A team of researchers recently encountered one such mystery while studying volcanic activities in the waters of the Solomon Islands. A video, captured by a specially-developed deep-sea camera, shows the rarely spotted Pacific sleeper shark living right inside an active volcano. Needless to say, the scientists are still grappling to understand how the organism managed to survive in such an inhospitable environment.

The researchers came across this bizarre occurrence while mapping the peak of Kavachi, one of the most active underwater volcanoes in the south-west part of the Pacific Ocean, near the Solomon Islands. Divers, who previously tried to reach the outer fringes of the volcano, reported mild skin burns, as a result of the heat emanating from the crater. Consequently, the scientists had to resort to using underwater cameras and robots, to get a better look at the volcano.

Earlier, this year, a team of researchers, led by Brennan Phillips of the University of Rhode Island, deployed several deep-sea cameras, including the National Geographic’s incredibly advanced Drop Cam, at a distance of around 12 miles (nearly 20 km) from Kavachi. It was while examining the video, filmed by one of these cameras, that the group actually came across a startling revelation. The 8-hour-long footage showed an entire community of sharks residing inside the still active volcano. After further investigation, the scientists were able to identify them as belonging to the Pacific sleeper, hammerhead and silky species of sharks. Phillips said:

These large animals are living in what you have to assume is much hotter and much more acidic water, and they’re just hanging out. It makes you question what type of extreme environment these animals are adapted to. What sort of changes have they undergone? Are there only certain animals that can withstand it? It is so black and white when you see a human being not able to get anywhere near where these sharks are able to go.

More puzzling, still, is the fact that sleeper sharks are endemic to the northern parts of the Pacific and the Atlantic oceans, as well as the waters surrounding Tasmania and Antarctica. The video, captured near the Solomon Islands, therefore marks the southernmost sighting of the species, to ever be reported. Speaking about the exciting possibilities, that the incident has created in the field of scientific research, Phillips said:

It opens up all kinds of questions. There are infinite directions in which we can go… It would be very interesting to pair observations of animal activity, such as the sharks, with actual eruptions of the main peak. Do they get an early warning and escape the caldera before it gets explosive, or do they get trapped and perish in steam and lava?